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  • Wait for tasks to get completed in threadpool.

    - by Alien01
    Hello I have created a thread pool in C++ which stores all tasks in a queue. Thread pool start n number of threads which takes tasks from queue , process each task and then delete tasks from queue. Now , I want to wait till all tasks get completed. Checking for empty queue for completion of tasks may not work as , task can be given to each thread and queue can be emptied but still the tasks can in processing mode. I am not getting idea how to wait for all the tasks completion.This is a design problem. Any suggestions?

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  • c# eventhandling error

    - by bragin.www
    i have method private void getValues(object sender, EventArgs e) { int id = int.Parse(dgvTable.Rows[dgvTable.CurrentRow.Index].Cells[0].Value.ToString()); var values = from c in v.db.TotalDoc where c.TotalID == id select c.TotalAmount; dgvValues.DataSource = values; } and datagridview "dgvTable" error at this line dgvTable.CellClick += new EventHadler(getValues); error text is: No overload for 'getValues' matches delegate 'System.EventHandler' please help!

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  • How can I get an IObservable<T> in Rx from a "non-standard" event?

    - by Dan Tao
    Here's what I mean. Suppose I'm working with an API that exposes events, but these events do not follow the standard EventHandler or EventHandler<TEventArgs> signature. One event might look like this, for instance: Public Event Update(ByVal sender As BaseSubscription, ByVal e As BaseEvent) Now, typically, if I want to get an IObservable<TEventArgs> from an event, I can just do this: Dim updates = Observable.FromEvent(Of UpdateEventArgs)( _ target:=updateSource, _ eventName:="Update" _ ) But this doesn't work, because the Update event is not an EventHandler<UpdateEventArgs> -- in fact, there is no UpdateEventArgs -- it's basically just its own thing. Obviously, I could define my own class deriving from EventArgs (i.e., UpdateEventArgs), write another class to wrap the object providing the Update event, give the wrapper class its own Update event that is an EventHandler<UpdateEventArgs>, and get an IObservable<UpdateEventArgs> from that. But that's an annoying amount of work. Is there some way to create an IObservable<[something]> from a "non-standard" event like this, or am I out of luck?

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  • Should I create protected constructor for my singleton classes?

    - by Vijay Shanker
    By design, in Singleton pattern the constructor should be marked private and provide a creational method retuning the private static member of the same type instance. I have created my singleton classes like this only. public class SingletonPattern {// singleton class private static SingletonPattern pattern = new SingletonPattern(); private SingletonPattern() { } public static SingletonPattern getInstance() { return pattern; } } Now, I have got to extend a singleton class to add new behaviors. But the private constructor is not letting be define the child class. I was thinking to change the default constructor to protected constructor for the singleton base class. What can be problems, if I define my constructors to be protected? Looking for expert views....

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  • How do I send a client-event asynchronously to a GtkWidget?

    - by fret
    I'm trying to send and receive a client-event using a GtkWidget on the win32 platform. The sending code looks like this: GtkWidget *Wnd; GdkNativeWindow Hnd = #ifdef WIN32 GDK_WINDOW_HWND(Wnd->window); #else GDK_WINDOW_XWINDOW(Wnd->window); #endif GdkEvent *Event = gdk_event_new(GDK_CLIENT_EVENT); // fill out Event params gdk_event_send_client_message(Event, Hnd); Receiving code looks like this: static gboolean MyClientEvent(GtkWidget *widget, GdkEventClient *ev, MyWnd *Wnd) { // breakpoint here... return TRUE; } GtkWidget *Wnd = gtk_window_new(GTK_WINDOW_TOPLEVEL); g_signal_connect( G_OBJECT(Wnd), "client-event", G_CALLBACK(MyClientEvent), this); gtk_widget_add_events(Wnd, GDK_ALL_EVENTS_MASK); I used Spy++ to see the message getting sent, so I know the sending side is ok. The receiving side however doesn't get the client-event. I was expecting my breakpoint in the callback to trigger... but it doesn't. I'm not even sure if a GtkWindow can receive a client-event... from past experience on X11 I thought it was pretty much the same as any other GtkWidget in that respect. Maybe on the win32 platform it's kinda different. But still I'd like to be able to get this working. I would like this to work with asynchronously, and in a thread-safe fashion, so that I can send events from worker threads up to the GUI thread.

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  • View artifacts leaking into the model of MVC

    - by Jono
    In an ASP.NET MVC application (which has very little chance of having its view technology ported to something non-HTML, but whose functional requirements evolve weekly,) how much HTML should ideally be allowed to be directly represented in the Model? I might come across as a design bigot for this, but I regard it as bad practice to allow any view constructs to "leak" into the model in an MVC application (and vice versa). For example, a Model that represents an item you're about to purchase should know nothing about the HTML check box that says "add giftwrap/message", nor should it know about any HTML drop down lists for payment card types. Conversely the View shouldn't be doing work like figuring out button text by translating keys into values (by looking in resource files.)

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  • Any ideas for developing a Risc Processor friendly string allocator?

    - by Richard Fabian
    I'm working on some tools to enable high throughput data-oriented development, and one thing that I've not got an immediate answer for is how you go about allocating strings quickly. On risc processors you've got another problem of implementation that the CPU doesn't like branching, which is what I'm trying to minimise or avoid. Also, cache coherence is important on most CPUs, so that's gotta be influential in the design too. So, how would you go about reducing the overhead for a generic string allocator? Sometimes it's easier to solve a more explicit problem, so any ideas for string sizes of 5-30?

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  • Is there such a thing as too many tables?

    - by Stacey
    I've been searching stackoverflow for about an hour now and couldn't find any topics related, so I apologize if this is a duplicate question. My inquery is this. Is there a point at which there are too many tables in a database? Even if the structure is well organized, thought out, and perfectly facilitates the design intent? I have a database that is quickly approaching 40 tables - about 10 main ones, and over 30 ancillary tables (junction tables, 'enumeration' tables, etc). Am I just a bad developer - or should I be trying something different? It seems like so many to me, I'm really afraid at how it will impact the performance of the project. I have done a lot of condensing where possible, grouped similar things where possible, etc. The database is built in MS-SQL 2008.

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  • Detecting GWT RichTextArea 'dirty' state

    - by David
    I want to detect when the contents of my GWT RichTextArea become 'dirty' (have been changed by the user) in order to enable a 'save' button accordingly. I suppose I could listen for key presses that are likely to have changed the contents; but browser support for key presses is notoriously quirky. I suppose I could, before editing begins, save the original contents in a variable, and upon key press, compare the current contents against that variable, but doing that on each key press is going to be really slow. Is there some neat way to achieve RichTextArea dirty-detection?

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  • C# Running several tasks at different intervals

    - by Nir
    A design question: I'd like to build a Windows service that executes different commands at different intervals. For simplicity's sake, let's say I want to run some batch files. The input it gets is a list of files and the intervals at which to execute. For example: a.bat - 4 minutes b.bat - 1 minute c.bat - 1 minute d.bat - 2 minutes I was thinking about sorting them according to intervals, and then setting a timer for each of the intervals. I'm not sure this is the best solution and I'd be happy to hear some feedbacks. Thanks!

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  • Fitts Law, applying it to touch screens

    - by Caylem
    Been reading a lot into UI design lately and Fitts Law keeps popping up. Now from what i gather its basically the larger an item is, and the closer it is to your cursor, the easier it is to click on. So what about touch screen devices where the input comes from multiple touches or just single touches. What are the fundamentals to take into account considering this? Should it be something like, the hands of the user are on the sides of the device so the buttons should be close to the left and right hand sides of the device? Thanks

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  • Designing constructors around type erasure in Java

    - by Internet Friend
    Yesterday, I was designing a Java class which I wanted to be initalized with Lists of various generic types: TheClass(List<String> list) { ... } TheClass(List<OtherType> list) { ... } This will not compile, as the constructors have the same erasure. I just went with factory methods differentiated by their names instead: public static TheClass createWithStrings(List<String> list) public static TheClass createWithOtherTypes(List<OtherType> list) This is less than optimal, as there isn't a single obvious location where all the different options for creating instances are available. I tried to search for better design ideas, but found surprisingly few results. What other patterns exist for designing around this problem?

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  • What do you do before starting on a project?

    - by hahuang65
    I'm still a pretty new project, and I haven't really worked on any large projects yet. However a few projects for school has shown me something I have never really thought of before. Pre-Project planning. One project we ran into a huge problem at the very last minute, and the other project was not divided up between partners very evenly, such that all the work was actually done at the end. So my question to everyone here is: How do you plan out the project beforehand? Please try to cover the following: Design (draw out UI by hand, UMLs, etc.) Division of Labor Timeline (especially how you estimate how much time is needed for certain things) and anything else you can think of. Thanks for all the help!

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  • Is this class + constructor definition pattern overly redundant?

    - by Protector one
    I often come across a pattern similar to this: class Person { public string firstName, lastName; public Person(string firstName, string lastName) { this.firstName = firstName; this.lastName = lastName; } } This feels overly redundant (I imagine typing "firstName" once, instead of thrice could be enough…), but I can't think of a proper alternative. Any ideas? Maybe I just don't know about a certain design pattern I should be using here? Edit - I think I need to elaborate a little. I'm not asking how to make the example code "better", but rather, "shorter". In its current state, all member names appear 3 times (declaration, initialization, constructor arguments), and it feels rather redundant. So I'm wondering if there is a pattern (or semantic sugar) to get (roughly) the same behavior, but with less bloat. I apologize for being unclear initially.

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  • Thread Management Object

    - by Gusdor
    I feel rather foolish as this is just a short question. I was reading about a bunch of thread management helper classes in .net, specifically one that aids the storage of threads to help a service manager object automatically invoke delegates onto the subscribing thread. I'm pretty sure it had something to do with creating dispatchers. Totally forgotten the name, can't find it :( Anyone know what I'm talking about?

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  • Doubt with c# handlers?

    - by aF
    I have this code in c# public void startRecognition(string pName) { presentationName = pName; if (WaveNative.waveInGetNumDevs() > 0) { string grammar = System.Environment.GetEnvironmentVariable("PUBLIC") + "\\SoundLog\\Presentations\\" + presentationName + "\\SpeechRecognition\\soundlog.cfg"; /* if (File.Exists(grammar)) { File.Delete(grammar); } executeCommand();*/ recContext = new SpSharedRecoContextClass(); recContext.CreateGrammar(0, out recGrammar); if (File.Exists(grammar)) { recGrammar.LoadCmdFromFile(grammar, SPLOADOPTIONS.SPLO_STATIC); recGrammar.SetGrammarState(SPGRAMMARSTATE.SPGS_ENABLED); recGrammar.SetRuleIdState(0, SPRULESTATE.SPRS_ACTIVE); } recContext.Recognition += new _ISpeechRecoContextEvents_RecognitionEventHandler(handleRecognition); //recContext.RecognitionForOtherContext += new _ISpeechRecoContextEvents_RecognitionForOtherContextEventHandler(handleRecognition); //System.Windows.Forms.MessageBox.Show("olari"); } } private void handleRecognition(int StreamNumber, object StreamPosition, SpeechLib.SpeechRecognitionType RecognitionType, SpeechLib.ISpeechRecoResult Result) { System.Windows.Forms.MessageBox.Show("entrei"); string temp = Result.PhraseInfo.GetText(0, -1, true); _recognizedText = ""; foreach (string word in recognizedWords) { if (temp.Contains(word)) { _recognizedText = word; } } } public void run() { if (File.Exists(System.Environment.GetEnvironmentVariable("PUBLIC") + "\\SoundLog\\Serialization\\Voices\\identifiedVoicesDLL.txt")) { deserializer = new XmlSerializer(_identifiedVoices.GetType()); FileStream fs = new FileStream(System.Environment.GetEnvironmentVariable("PUBLIC") + "\\SoundLog\\Serialization\\Voices\\identifiedVoicesDLL.txt", FileMode.Open); Object o = deserializer.Deserialize(fs); fs.Close(); _identifiedVoices = (double[])o; } if (File.Exists(System.Environment.GetEnvironmentVariable("PUBLIC") + "\\SoundLog\\Serialization\\Voices\\deletedVoicesDLL.txt")) { deserializer = new XmlSerializer(_deletedVoices.GetType()); FileStream fs = new FileStream(System.Environment.GetEnvironmentVariable("PUBLIC") + "\\SoundLog\\Serialization\\Voices\\deletedVoicesDLL.txt", FileMode.Open); Object o = deserializer.Deserialize(fs); fs.Close(); _deletedVoices = (ArrayList)o; } myTimer.Interval = 5000; myTimer.Tick += new EventHandler(clearData); myTimer.Start(); if (WaveNative.waveInGetNumDevs() > 0) { _waveFormat = new WaveFormat(_samples, 16, 2); _recorder = new WaveInRecorder(-1, _waveFormat, 8192 * 2, 3, new BufferDoneEventHandler(DataArrived)); _scaleHz = (double)_samples / _fftLength; _limit = (int)((double)_limitVoice / _scaleHz); SoundLogDLL.MelFrequencyCepstrumCoefficients.calculateFrequencies(_samples, _fftLength); } } startRecognition is a method for Speech Recognition that load a grammar and makes the recognition handler here: recContext.Recognition += new _ISpeechRecoContextEvents_RecognitionEventHandler(handleRecognition); Now I have a problem, when I call the method startRecognition before method run, both handlers (the recognition one and the handler for the Tick) work well. If a word is recognized, handlerRecognition method is called. But, when I call the method run before the method startRecognition, both methods seem to run well but then the recognition Handler is never executed! Even when I see that words are recognized (because they happear on the Windows Speech Recognition app). What can I do for the recognition handler be allways called?

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  • How big teams work with database

    - by Michael Riva
    Lets say I have a team, 20 developers. And we are making a project on .net. In team every one can easy create their tables according to their modules working on it. And we think to use an ORM, can you tell me how can and which ORM tools for good to working with team. Is there any proven way? I m asking becouse I never work with a team, so I dont know the best practices. So you guys what kind of pattern you use?. I realy wonder. The team members can write their unit tests and supply necessary design patterns. What kind of approach I need to create to manage team? What kind of ORM tools that we have to use?

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  • business object and codelist

    - by feiroox
    Hi How to design a business object? I have a library which returns me an Object which have ten lists of other different objects. I need to store it into database all. List of objects are often like: class Item { private int id; private String name; private double point; } But the name is often the same. Like basic title of the product or code. Containing from 3 characters up to 70characters. Should I make conversion for every Object to: (or something similar) class ConvertedItem { private int id; private int code; private double point; } And have a separated table of codes ( I guess around 60). Or do not bother with duplicated stuff? It's not mission critical app. What would you do in my case? thanks in advance

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  • What are some best practices for making sure your .NET code will scale well?

    - by billmaya
    Last week I interviewed for a position at a TripleA MMORPG game company here in NE. I didn't get the job but one of the areas that came up during the interview was the about the scalability of the code that you write and how it should be considered early on in the design of your architecture and classes. Sadly to say I've never thought very much about the scalability of the .NET code that I've written (I work with single user desktop and mobile applications and our major concerns are usually with device memory and rates of data transmission). I'm interested in learning more about writing code that scales up well so it can handle a wide range of remote users in a client server environment, specifically MMORPGs. Are there any books, web sites, best practices, etc. that could get me started researching this topic?

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  • Update function

    - by kosmaks
    Hello everyone! I try to learn java for android devices.. i have to create the update function. But still have one question: How???? in class root public void update(){ maindebug("update"); // This is my debug function } public void run(){ while(isRunning){ // isRunning is a boolean variable SystemClock.sleep(100); update(); } } and inside onCreate run(); but it doesnt work :(

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  • Designing a recipe database that needs to include ingredients as well as sub-recipes

    - by VinceL
    I am designing a recipe database that needs to be very flexible as it is going to be communicating directly with our back-of-house inventory system. This is what I have so far in regards to the tables: Recipe: this table will contain the recipe date: the name, steps needed to cook, etc. Ingredients/Inventory: this is our back of house inventory, so this will have the information about each product that will be used in our recipes. Recipe Line Item: This is the tricky table, I want to be able link to the ingredients here as well as the quantity needed for the recipe, but I also need to be able to directly include recipes from the recipe table (such as marinara sauce that we make in-house), and that is why I am having trouble figuring out the best way to design this table. Basically, the recipe line item table needs to be able to link to either the ingredients table or the recipe table depending on which line item is needed and I want to know what would be the most effective way to handle that. Thank you so much in advance!

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